<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2017/9/20
 * Time: 14:36
 */
$str = 'Appleround,apPlered,applejuicyapplesweet';
echo str_ireplace('APPle', 'banana', $str);

    $email = "ahjunchen@QQ.COM";
var_dump(stripos($email,"qq.com"));